A problem in multimedia messaging services is that terminals have very different capabilities (supported media formats, maximum image resolution, maximum message size, etc.). This creates interoperability problems. To reduce this problem, multimedia messaging service centers (MMSC) can adapt messages to the specific terminal capabilities. These capabilities are obtained through UAProf or deduced from HTTP/WSP headers such as a User Agent header (UAHEADER) and Accept headers. However, there are cases where the MMSC cannot adapt without significantly deteriorating the quality of the content or it does not have the functionality to do so. An example of the first case is converting a video clip to an image (e.g. extracting the first frame of the video clip). An example of the second case is if the message contains an image in PNG format (not supported by the receiving terminal) and the MMSC cannot convert PNG to an image format supported by the terminal (e.g. converting PNG to GIF). In these cases, user experience is drastically reduced.
In the current state of the art, the MMSC tries its best to adapt each media component to a format that is supported by the terminal (based on the reported capabilities). However, the MMSC transcoding capabilities may be limited only to a small set of formats. For example, the Nokia MMSC can convert GIF to JPEG and video to JPEG but those are about the only image format conversions supported so far. When the message quality is reduced too much, the message can also be forwarded to an e-mail address or legacy terminal support (some Web server for messages). Nevertheless usability is significantly reduced at a receiving terminal (e.g. when converting a video clip to a single image). For many other formats (PNG, PBM, etc.), the MMSC cannot perform the adaptation at all. Those components are still sent to the terminal if they fit within the multimedia messaging service message size restriction, but they may be unusable on the terminal side.
Thus, it is desirable to increase interoperability between terminals by providing an easy way for terminals to render originally unsupported components of the multimedia messages. It is also desirable to improve the user experience by providing easy assurance that messages can be adapted and to avoid cases where the MMSC just sending an unsupported component (with which the terminal doesn't know what to do) or dropping it. It is further desirable to increase performance of already deployed mobile phones.